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US5161238A - Apparatus for confining laser beams - Google Patents

Apparatus for confining laser beams Download PDF

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Publication number
US5161238A
US5161238A US07331246 US33124689A US5161238A US 5161238 A US5161238 A US 5161238A US 07331246 US07331246 US 07331246 US 33124689 A US33124689 A US 33124689A US 5161238 A US5161238 A US 5161238A
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US
Grant status
Grant
Patent type
Prior art keywords
beam
laser
diaphragm
portions
wall
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07331246
Inventor
Bernd Mehmke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lambda Physik AG
Original Assignee
Lambda Physik Forschungs und Entwicklungs GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B27/00Other optical systems; Other optical apparatus
    • G02B27/09Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G02B27/0938Using specific optical elements
    • G02B27/0988Diaphragms, spatial filters, masks for removing or filtering a part of the beam
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/066Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms by using masks
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B27/00Other optical systems; Other optical apparatus
    • G02B27/09Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/005Diaphragms
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01SDEVICES USING STIMULATED EMISSION
    • H01S3/00Lasers, i.e. devices for generation, amplification, modulation, demodulation, or frequency-changing, using stimulated emission, of infra-red, visible, or ultra-violet waves
    • H01S3/005Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping

Abstract

An apparatus for confining or limiting laser beams of medium and high power comprises a diaphragm 1, 1' which is mirrored and is arranged with respect to the laser beam 2 in such a manner that the beam portions (3, 3') reflected by the diaphragm are directed away from the laser beam axis A.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an apparatus for confining laser beams of medium and high power with a diaphragm confining the laser beam.

2. Description of Related Art

For a great variety of reasons it is frequently necessary to geometrically confine or restrict laser beams. For example, it may be necessary to adapt the dimensions of the laser beam to a given optical system, generate a beam with a specifically configured cross-section, produce sharp beam boundaries or reduce the beam opening angle.

In the prior art for confining the laser beam diaphragms are usually employed which absorb the unrequired parts of the laser beam. The diaphragms may have various forms depending on the desired dimensions of the confined or limited laser beam. Usually, circular pinhole or rectangular slit diaphragms are employed, depending on whether the dimension of the laser beam is to be limited in one or two dimensions. Diaphragms may be arranged in the laser beam outside the laser (extracavity) or in the laser resonator (intracavity).

The known diaphragm arrangements involve however problems when the power of the laser lies in the medium or higher range, i.e. is a few Watts or more. Since the known diaphragms limit the beam by absorption of beam components the diaphragms can become very hot and assume temperatures of more than 100° C. This heating of the diaphragms leads to a heating of the surrounding air and as a result schliere formation can occur at the edges. The density of the air changes directly at the edges of the diaphragm so that inhomogeneity of the refractive index occurs in said region and this causes the schliere formation.

Such schliere formation or streaks disturb the rectilinear propagation of the laser beam. The schliere formation impairs the quality of the laser beam and under unfavourable conditions may even partially cancel the effect of one or more diaphragms which are intended to sharply restrict the beam or confine the beam opening angle. Due to the schliere formation the edge parts of the laser beam are irregularly diffracted so that the sharp edge boundaries become blurred again and parts of the beam can be reflected into precisely those directions which the diaphragms are intended to block off.

SUMMARY OF THE INVENTION

The invention is based on the problem of providing an apparatus for confining laser beams of medium and high power which with simple means ensures a sharp beam boundary without interferences.

According to the invention this problem is solved in that the laser beam is confined by a diaphragm which is at least partially measured and is arranged with respect to the laser beam in such a manner that the beam portions reflected by the diaphragm are directed away from the laser beam axis. The term "directed away from" is to be taken as meaning that the reflected beam portions are removed from the laser beam. In being so they can previously intersect the beam axis.

Due to the mirroring of the diaphragm provided according to the invention a negligibly small heating up thereof or none at all takes place. The energy of the shut-out beam portions is substantially reflected, i.e. carried away from the diaphragm. The diaphragm is mirrored to such an extent that at the wavelength of the laser beam it is not absorbent or is only negligibly absorbent, i.e. absorbs only a few percent.

Since due to the good direction characteristic of the laser, the beam portions reflected by the diaphragm are likewise relatively sharply aligned, they can be reflected completely out of the laser beam and directed onto an absorber which is arranged at an adequate distance from the laser beam to ensure that any possible heating of the absorber cannot cause any disturbances of the laser beam.

Thus, according to the invention the mirrored diaphragms are arranged with respect to the laser beam axis in such a manner that the mirror surfaces form an angle other than 90° with the beam axis.

Hereinafter examples of the invention will be described with the aid of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 3 show various embodiments of apparatuses for confining laser beams of medium and high power.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to FIG. 1 a diaphragm 1, 1' is arranged in the optical path of the laser beam 2 having an optical beam axis A. The Figure shows a horizontal section through the diaphragm which has wall portions 4, 4 bounding an opening 5 that for example may be slit-shaped or circular. With a circular diaphragm FIG. 1 would also represent a vertical section.

The beam portions 3, 3' of the laser beam 2 are blocked and reflected the wall portions 4, 4' of the diaphragm 1, 1' and are directed away from the laser beam axis in two rays extending in opposite directions generally normal to the beam axis and remote from the laser beam 2 to be intercepted by a suitable absorber (not shown).

The diaphragm 1, 1' is mirrored at least at the blocking wall portions 4, 4 upon which the incident laser beam 2 impinges. The diaphragm may be polished metal, specially coated glass or other type of mirror, each serving as a light reflector.

FIGS. 2 and 3 show modifications of the embodiment according to FIG. 1 and will be immediately understood. The variant according to FIG. 3 has the advantage that the reflected beam portions 3, 3' are directed in the same direction generally normal to the beam axis so that they can be intercepted by a single absorber. In the variant according to FIG. 2, it is possible to configure the mirror surfaces of the blocking wall portions 4, 4 in such a manner that the reflected beam portions 3, 3' can be directed along intersecting paths and selectively onto a specific target. Also, the reflected beams portions 3, 3' may themselves be used as auxiliary beam.

Claims (5)

I claim:
1. A heat-resistant diaphragm for confining a medium/high power laser beam having an optical axis and directed along an optical path, comprising:
wall portions in the optical path and bounding an opening through which a part of the laser beam passes, at least one of the wall portions blocking another part of the laser beam impinging on said at least one blocking wall portion from passing through the opening; and
a light reflector on said at least one blocking wall portion for reflecting the other part of the laser beam impinging directly on said at least one blocking wall portion away from the light reflector and in a direction inclined relative to the optical axis, thereby resisting heat build-up at said at least one blocking wall portion due to direct exposure to the medium/high power laser beam.
2. The diaphragm according to claim 1, wherein there are two wall portions blocking the other part of the laser beam, said two wall portions being spaced apart of each other at opposite sides of the optical axis; and wherein there are two light reflectors, one for each blocking wall portion.
3. The diaphragm according to claim 2, wherein the two wall portions and light reflectors are positioned to reflect the other part of the laser beam in two rays extending in opposite directions generally normal to the optical axis.
4. The diaphragm according to claim 2, wherein the two wall portions and light reflectors are positioned to reflect the other part of the laser beam in two rays extending in the same direction generally normal to the optical axis.
5. The diaphragm according to claim 2, wherein the two wall portions and light reflectors are positioned to reflect the other part of the laser beam in two rays extending in intersecting relationship with each other.
US07331246 1988-05-27 1989-03-31 Apparatus for confining laser beams Expired - Fee Related US5161238A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE19883818129 DE3818129C2 (en) 1988-05-27 1988-05-27 Means for limiting of laser beams
DE3818129 1988-05-27

Publications (1)

Publication Number Publication Date
US5161238A true US5161238A (en) 1992-11-03

Family

ID=6355298

Family Applications (1)

Application Number Title Priority Date Filing Date
US07331246 Expired - Fee Related US5161238A (en) 1988-05-27 1989-03-31 Apparatus for confining laser beams

Country Status (3)

Country Link
US (1) US5161238A (en)
JP (1) JPH0232580A (en)
DE (1) DE3818129C2 (en)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5381439A (en) * 1993-06-14 1995-01-10 The United States Of America As Represented By The United States Department Of Energy Laser dividing apparatus
US6327090B1 (en) 1997-07-03 2001-12-04 Levelite Technology, Inc. Multiple laser beam generation
EP1192484A1 (en) * 1999-05-17 2002-04-03 Toolz, Ltd. Self-leveling penta laser beam device
US6381256B1 (en) 1999-02-10 2002-04-30 Lambda Physik Ag Molecular fluorine laser with spectral linewidth of less than 1 pm
US6414438B1 (en) 2000-07-04 2002-07-02 Lambda Physik Ag Method of producing short-wave radiation from a gas-discharge plasma and device for implementing it
US6424666B1 (en) 1999-06-23 2002-07-23 Lambda Physik Ag Line-narrowing module for high power laser
US6463086B1 (en) 1999-02-10 2002-10-08 Lambda Physik Ag Molecular fluorine laser with spectral linewidth of less than 1 pm
US20020167652A1 (en) * 2001-05-14 2002-11-14 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
US20020168049A1 (en) * 2001-04-03 2002-11-14 Lambda Physik Ag Method and apparatus for generating high output power gas discharge based source of extreme ultraviolet radiation and/or soft x-rays
US6546037B2 (en) 1999-02-10 2003-04-08 Lambda Physik Ag Molecular fluorine laser with spectral linewidth of less than 1 pm
US6577663B2 (en) 2000-06-19 2003-06-10 Lambda Physik Ag Narrow bandwidth oscillator-amplifier system
US20040207934A1 (en) * 2001-12-04 2004-10-21 Rash Clarence E. Interchangeable low-backscatter aperture structure
US20060119919A1 (en) * 2004-12-03 2006-06-08 Microvision, Inc. Aperture plate and related system and method
US7075963B2 (en) 2000-01-27 2006-07-11 Lambda Physik Ag Tunable laser with stabilized grating
EP1758216A1 (en) * 2005-08-26 2007-02-28 Trumpf Laser- und Systemtechnik GmbH Two-stage diaphragm for a laser beam
WO2007048507A1 (en) * 2005-10-28 2007-05-03 Carl Zeiss Laser Optics Gmbh Beam separating optical element
EP1850165A1 (en) * 2006-04-27 2007-10-31 Ricoh Company, Ltd. Light Source System, Optical Scanner, Image Forming Apparatus, Light-Amount Control Method, Optical Scanning Method, and Image Forming Method
US7714998B2 (en) 2006-11-28 2010-05-11 Applied Materials South East Asia Pte. Ltd. Image splitting in optical inspection systems
US7719674B2 (en) * 2006-11-28 2010-05-18 Applied Materials South East Asia Pte. Ltd. Image splitting in optical inspection systems
US20130170023A1 (en) * 2010-08-02 2013-07-04 Leica Microsystems Cms Gmbh Device for Continuous Adjustment of Spectrometer Gap Widths
CN105182545A (en) * 2015-08-26 2015-12-23 北京国科世纪激光技术有限公司 Laser device
US9762024B2 (en) 2013-09-27 2017-09-12 Gigaphoton Inc. Laser apparatus and extreme ultraviolet light generation system

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69314791T2 (en) * 1992-06-11 1998-07-09 Zed Instr Ltd printhead
WO2000014588A1 (en) * 1998-09-07 2000-03-16 Carl Zeiss Jena Gmbh Device for improving the beam product
DE19929436A1 (en) * 1999-06-26 2001-01-11 Hilti Ag Beam splitter for splitting a light beam into sub-beams
DE10033786A1 (en) * 2000-07-12 2002-01-31 Baasel Carl Lasertech Prism-shaped stop has aperture in first surface for total internal reflection of light incident normally on second surface, opening between aperture, second surface for passage of laser light
DE102008036568B4 (en) 2008-07-31 2011-05-05 Carl Zeiss Laser Optics Gmbh Device for the lateral limit of a laser beam
DE102009053715A1 (en) * 2009-11-19 2011-05-26 Feha Lasertec Halle Gmbh Laser device for engraving printing rollers
NL2013518A (en) * 2013-09-25 2015-03-30 Asml Netherlands Bv Beam delivery apparatus and method.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3578849A (en) * 1968-07-23 1971-05-18 Commissariat Energie Atomique Diaphragm for a laser amplifier chain
US4940308A (en) * 1988-06-27 1990-07-10 Eastman Kodak Company Laser beam stop

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3639580C2 (en) * 1985-11-20 1991-02-14 Mitsubishi Denki K.K., Tokio/Tokyo, Jp

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3578849A (en) * 1968-07-23 1971-05-18 Commissariat Energie Atomique Diaphragm for a laser amplifier chain
US4940308A (en) * 1988-06-27 1990-07-10 Eastman Kodak Company Laser beam stop

Cited By (41)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5381439A (en) * 1993-06-14 1995-01-10 The United States Of America As Represented By The United States Department Of Energy Laser dividing apparatus
US6327090B1 (en) 1997-07-03 2001-12-04 Levelite Technology, Inc. Multiple laser beam generation
US6463086B1 (en) 1999-02-10 2002-10-08 Lambda Physik Ag Molecular fluorine laser with spectral linewidth of less than 1 pm
US6546037B2 (en) 1999-02-10 2003-04-08 Lambda Physik Ag Molecular fluorine laser with spectral linewidth of less than 1 pm
US6381256B1 (en) 1999-02-10 2002-04-30 Lambda Physik Ag Molecular fluorine laser with spectral linewidth of less than 1 pm
US6490306B2 (en) 1999-02-10 2002-12-03 Lambda Physik Ag Molecular fluorine laser with spectral linewidth of less than 1 pm
EP1192484A4 (en) * 1999-05-17 2003-01-15 Toolz Ltd Self-leveling penta laser beam device
EP1192484A1 (en) * 1999-05-17 2002-04-03 Toolz, Ltd. Self-leveling penta laser beam device
US6542304B2 (en) 1999-05-17 2003-04-01 Toolz, Ltd. Laser beam device with apertured reflective element
US6560254B2 (en) 1999-06-23 2003-05-06 Lambda Physik Ag Line-narrowing module for high power laser
US6424666B1 (en) 1999-06-23 2002-07-23 Lambda Physik Ag Line-narrowing module for high power laser
US7075963B2 (en) 2000-01-27 2006-07-11 Lambda Physik Ag Tunable laser with stabilized grating
US6577663B2 (en) 2000-06-19 2003-06-10 Lambda Physik Ag Narrow bandwidth oscillator-amplifier system
US6414438B1 (en) 2000-07-04 2002-07-02 Lambda Physik Ag Method of producing short-wave radiation from a gas-discharge plasma and device for implementing it
US6804327B2 (en) 2001-04-03 2004-10-12 Lambda Physik Ag Method and apparatus for generating high output power gas discharge based source of extreme ultraviolet radiation and/or soft x-rays
US20020168049A1 (en) * 2001-04-03 2002-11-14 Lambda Physik Ag Method and apparatus for generating high output power gas discharge based source of extreme ultraviolet radiation and/or soft x-rays
EP1637909A3 (en) * 2001-05-14 2006-04-12 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
EP1258743A3 (en) * 2001-05-14 2004-05-12 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
EP1258743A2 (en) * 2001-05-14 2002-11-20 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
US6816237B2 (en) 2001-05-14 2004-11-09 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
US20020167652A1 (en) * 2001-05-14 2002-11-14 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
EP1637909A2 (en) 2001-05-14 2006-03-22 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
US6927924B2 (en) 2001-05-14 2005-08-09 Dainippon Screen Mfg. Co., Ltd. Imaging optical instrument
US6896377B2 (en) 2001-12-04 2005-05-24 The United States Of America As Represented By The Secretary Of The Army Interchangeable low-backscatter aperture structure
US20040207934A1 (en) * 2001-12-04 2004-10-21 Rash Clarence E. Interchangeable low-backscatter aperture structure
US6834971B2 (en) * 2001-12-04 2004-12-28 The United States Of America As Represented By The Secretary Of The Army Low-backscatter aperture structure
US20060119919A1 (en) * 2004-12-03 2006-06-08 Microvision, Inc. Aperture plate and related system and method
WO2006091253A2 (en) * 2004-12-03 2006-08-31 Microvision, Inc. Aperture plate and related sytem and method
WO2006091253A3 (en) * 2004-12-03 2006-11-30 Microvision Inc Aperture plate and related sytem and method
US7277213B2 (en) 2004-12-03 2007-10-02 Microvision, Inc. Aperture plate and related system and method
EP1758216A1 (en) * 2005-08-26 2007-02-28 Trumpf Laser- und Systemtechnik GmbH Two-stage diaphragm for a laser beam
WO2007048507A1 (en) * 2005-10-28 2007-05-03 Carl Zeiss Laser Optics Gmbh Beam separating optical element
EP1850165A1 (en) * 2006-04-27 2007-10-31 Ricoh Company, Ltd. Light Source System, Optical Scanner, Image Forming Apparatus, Light-Amount Control Method, Optical Scanning Method, and Image Forming Method
US8085457B2 (en) 2006-04-27 2011-12-27 Ricoh Company, Ltd. Light source system, optical scanner, image forming apparatus, and light-amount control method
US7719674B2 (en) * 2006-11-28 2010-05-18 Applied Materials South East Asia Pte. Ltd. Image splitting in optical inspection systems
US7714998B2 (en) 2006-11-28 2010-05-11 Applied Materials South East Asia Pte. Ltd. Image splitting in optical inspection systems
US20130170023A1 (en) * 2010-08-02 2013-07-04 Leica Microsystems Cms Gmbh Device for Continuous Adjustment of Spectrometer Gap Widths
US8837044B2 (en) * 2010-08-02 2014-09-16 Leica Microsystems Cms Gmbh Device for continuous adjustment of spectrometer gap widths
US20150002917A1 (en) * 2010-08-02 2015-01-01 Leica Microsystems Cms Gmbh Device for continuous adjustment of spectrometer gap widths
US9762024B2 (en) 2013-09-27 2017-09-12 Gigaphoton Inc. Laser apparatus and extreme ultraviolet light generation system
CN105182545A (en) * 2015-08-26 2015-12-23 北京国科世纪激光技术有限公司 Laser device

Also Published As

Publication number Publication date Type
DE3818129C2 (en) 2003-04-10 grant
DE3818129A1 (en) 1989-11-30 application
JPH0232580A (en) 1990-02-02 application

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Owner name: LAMBDA PHYSIK FORSCHUNGS-UND ENTWICKLUNGSGESELLSCH

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Effective date: 19890315

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Effective date: 20041103